US Bridges

Castle RD over Unnamed Str

Fair

Linn County, Missouri · S 16 T 58 N R 21 W · Structure no. 20385

Built
1978
47 years old
Condition
Fair
inspected December 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
29 ft
1 main span
Daily traffic
30
2024 count
Owner
County
County Highway Agency

About this bridge

Castle RD over Unnamed Str is a steel stringer/multi-beam or girder carrying Castle RD over Unnamed Str in Linn County, Missouri. It was built in 1978, so it is 47 years old, older than the Missouri average of 45.1 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 30 vehicles a day, roughly 10% of them trucks, projected to reach 33 by 2044. The structure is 29 ft (8.8 m) long and 14 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

Open in Google Maps
CarriesCastle RD
CrossesUnnamed Str
LocationS 16 T 58 N R 21 W
RouteCounty Highway 257
CountyLinn County
StateMissouri
Coordinates39.84994, -93.26816
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionDecember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating38.7 US tons
Inventory rating24.8 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadOther
Structure length29 ft (8.8 m)
Longest span28 ft (8.5 m)
Deck width14 ft (4.3 m)
Roadway width14 ft (4.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30 (2024)
Projected traffic33 by 2044
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed0.6 mi (1 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Castle RD over Unnamed Str built?

It was built in 1978, making it 47 years old in 2025.

What condition is Castle RD over Unnamed Str in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in December 2024.

How much traffic does Castle RD over Unnamed Str carry?

About 30 vehicles per day (2024 count), of which roughly 10% are trucks.

How long is Castle RD over Unnamed Str?

The structure is 29 ft (8.8 m) long with a longest span of 28 ft (8.5 m) and a deck 14 ft wide.

Who owns Castle RD over Unnamed Str?

It is owned by the County Highway Agency.